Electric drive vehicles are a promising technology for reducing both greenhouse gas emissions and dependence on fossil fuels. The market share for plug-in hybrid electric vehicles (PHEV) and pure electric vehicles (EVs) has increased significantly in recent years. Despite offering the advantages of energy efficiency and low environmental impact, market penetration of EVs has been limited because of their relatively short driving range. Compared to gasoline powered vehicles which typically have a driving range of over 300 mile before refueling, current generation EVs can achieve only 100 to 200 miles before recharging. Furthermore, the driving range for EVs is greatly reduced in cold environments.
At subzero temperatures, the driving range of an EV is further adversely affected due to the poor discharge and regen power of the battery. The poor performance of Li-ion batteries in EVs, for example, is closely related to significantly reduced energy and power capabilities of such batteries, as well as capacity fade due to lithium plating upon charging. See G. Nagasubramanian, J Appl Electrochem, 31 (2001) 99-104; S. S. Zhang, K. Xu, T. R. Jow, Electrochim Acta, 49 (2004) 1057-1061; H.P. Lin, D. Chua, M. Salomon, H. C. Shiao, M. Hendrickson, E. Plichta, S. Slane, Electrochem Solid St, 4 (2001) A71-A73; J. Fan, S. Tan, J Electrochem Soc, 153 (2006) A1081-A1092.
Fundamentally, the poor performance of Li-ion batteries at subzero temperatures arises from sluggish kinetics of charge transfer, low electrolyte conductivity and reduced solid-state Li diffusivity. See C. K. Huang, J. S. Sakamoto, J. Wolfenstine, S. Surampudi, J Electrochem Soc, 147 (2000) 2893-2896; S. S. Zhang, K. Xu, T. R. Jow, J Power Sources, 115 (2003) 137-140; M. C. Smart, B. V. Ratnakumar, S. Surampudi, J Electrochem Soc, 146 (1999) 486-492; M. C. Smart, B. V. Ratnakumar, S. Surampudi, J Electrochem Soc, 149 (2002) A361-A370; S. S. Zhang, K. Xu, T. R. Jow, Electrochim Acta, 48 (2002) 241-246. While these limitations might be alleviated by finding more suitable electrolyte and active materials, an alternative approach is to devise a system to quickly pre-heating the battery to normal operation temperature before use. Since the kinetic and transport processes are highly temperature dependent, cell performance will quickly recover during warm up. See M. D. Zolot, et al., Thermal Evaluation of The Honda Insight Battery Pack, in 36th Intersociety Energy Conversion Engineering Conference, Savannah, Ga., 2001, pp. 923; A. Pesaran, et al., Cooling and Preheating of Batteries in Hybrid Electric Vehicles, in The 6th ASME-JSME Thermal Engineering Joint Conference, Hawaii Island, Hi., 2003.
Various attempts to heat batteries in electric or hybrid electric vehicles have been disclosed. U.S. Pat. No. 6,072,301 discloses a resonant self-heating battery electric circuit to heat a battery prior to use. The electrical circuit requires the use of storage circuit for storing energy. U.S. Pat. No. 6,441,588 relates to a battery charging method that includes pulse charging and discharging operations to heat a battery prior to charging the battery. The pulse charging and discharging operations are applied to the battery as a whole by a charger that is external to the battery. U.S. Patent Publication No. 2009/0087723 A1 discloses use of a heater built in the battery that is electrically insulated from electrode terminals.
However, a continuing need exists to ameliorate the reduced performance of rechargeable batteries subject to cold temperatures.